The habitatofVaranus rudicollis is limited to primary and secondary rainforest and mangrove swamps.[7] In the wild the black rough-necked monitor is very rarely seen, but whether this is because of its rarity or its very secretive behavior is uncertain.[3] They are often kept successfully in captivity, but have a shy disposition.[3][8]
The black roughneck is a medium to large monitor. It usually reaches an average adult size of 3–4 ft. (90–120 cm), with a maximum length of 5 feet (150 cm), reported.[8] The black rough-necked monitor can be easily recognized by large pointed scales adorning the necks of adults.[4] They are a gracile, long-bodied lizard with a prominently pointed snout. Black roughnecks are known for their very calm temperament, rarely biting or tail whipping in captivity. When threatened they prefer to escape, urinate or defecate, puff up their throats or “go necrotic” by closing their eyes as if playing dead.
The dietary habits of black rough-necked monitors have been the subject of various studies. Early research by Schnider (in Werner 1900) found insects in specimen from Sumatra. Mertens (1942) suggested that ants and possibly termites were a significant part of their diet, collected using their tongue. Auffenberg (1988) supported this by discovering termites, large stick insects, and tree centipedes in specimens from Malaysia. Brandenberg (1983) found a stomach full of large cockroaches and grasshoppers in one individual, while another from Surat Thani in Thailand had a stomach full of crabs (Nabhitabhata, pers. comm.). Further research by Losos and Greene (1988) revealed that the diet of V. rudicollis may include frogs and their eggs, spiders, scorpions, crabs, cockroaches, beetles, and orthopterans.[11]
These monitors may remain active throughout the year, with their presence most noticeable during months of heavy rainfall
Amer, Sayed A. M. and Yoshinori Kumazawa 2008. Timing of a mtDNA gene rearrangement and intercontinental dispersal of varanid lizards. Genes Genet. Syst. 83: 275–280
Auliya, M. (2006). Taxonomy, Life History, and conservation of giant reptiles in west Kalimantan. Natur und Tier Verlag, Münster, 432 pp.
Ávalos, J. de & Martínez Carrión, P. (1997). Warane Reptilia (Münster) 2 (5): 16-21
Barbour, Thomas (1932). A new Bornean monitor Proceedings of the New England Zoological Club 13: 1-2
Bayless, Mark K. 1997. The rough-neck Monitor lizard (Varanus rudicollis) Bulletin of the Chicago Herpetological Society 32 (12): 250-252
Bennett, Daniel 1993. A review of some literature concerning the rough-necked monitor lizard Varanus rudicollis Reptilian 1 (9): 7-10
Bennett, Daniel; Liat, Lim Boo 1995. A note on the distribution of Varanus dumerilii and V. rudicollis in Peninsular Malaysia. Malayan Nature Journal 49(2):113-116.
Bong Heang, Kiew 1987. An annotated checklist of the herpetofauna of Ulu Endau, Johore, Malaysia Malayan Nature J. 41(2-3): 413-423.
Boulenger, G.A. 1885. Catalogue of the lizards in the British Museum (Natural History). Vol. 2, Second edition. London, xiii+497 pp.
De Rooij, N. de 1915. The Reptiles of the Indo-Australian Archipelago. I. Lacertilia, Chelonia, Emydosauria. Leiden (E. J. Brill), xiv + 384 pp.
Gaulke, Maren 1991. Systematic relationships of the Philippine water monitors as compared with Varanus s. salvator, with a discussion of dispersal routes Mertensiella 2: 154-167
Gray, J. E. 1845. Catalogue of the specimens of lizards in the collection of the British Museum. Trustees of die British Museum/Edward Newman, London: xxvii + 289 pp.
Horn,H.G. & Peters,G. 1982. Beiträge zur Biologie des Rauhnackenwarans, Varanus (Dendrovaranus) rudicollis Gray. Salamandra 18 (1/2): 29-40
MANGILI (1962). Giard. zool. Roma, 4: 30
Manthey, U. & Grossmann, W. (1997). Amphibien & Reptilien Südostasiens. Natur und Tier Verlag (Münster), 512 pp.
Taylor, E.H. 1963. The lizards of Thailand. Univ. Kansas Sci. Bull. 44: 687-1077.
Werner, F. 1900. Reptilien und Batrachier aus Sumatra, gesammelt Herrn. Gustav Schneider jr., im Jahre 1897-1898. Zool.Jahrb. (syst) 13:479-508
